FRONTIERS OF ZOOLOGYDale A. Drinnon has been a researcher in the field of Cryptozoology for the past 30+ years and has corresponded with Bernard Heuvelmans and Ivan T. Sanderson. He has a degree in Anthropology from Indiana University and is a freelance artist and writer. Motto: "I would rather be right and entirely alone than wrong in the company with all the rest of the world"--Ambroise Pare', "the father of modern surgery", in his refutation of fake unicorn horns.

Thursday, 9 May 2013

The type of the PostCretaceous Plesiosaur

SOURCE
This passage is comparing the late Plesiosaurian genera Elasmosaurus and Cimiolasaurus: It is not certain that Elasmosaurus was a fast swimmer because its very long neck must have made it awkward. However, the other Plesiosaur was not of a type that would have gone after Elasmosaurus, it ate smallish fishes and squids instead.

Fossils of the type species for Cimoliasaurus from a geologically ambiguous stratum in New Jersey. The vertebrae are very distinctive from oyher plesiosaur vertebrae, such as those of the Elasmosaurs, and are more cupped at the ends rather than being relatively flat. This is thought to indicate a more flexible spine, and especially a more flexible neck, for the animal in life. a second find of the supposed genus was found in Alabama and initially marked as coming from Eocene (Zueglodon-bed) deposits, and was given the now-obsolete name of Discosaurus.

Cimoliasaurus(Sometimes spelled as Cimoliosaurus‭)

Name: Cimoliasaurus.Phonetic:
Sim-o-le-ah-sore-us.Named By: Joseph Liedy‭ ‬-‭
‬1851.Synonyms: Cimoliasaurus brevior,‭ ‬Cimoliasaurus maccoyi,‭
‬Discosaurus,‭ ‬Oligosimus,‭ ‬Piptomerus.Classification:
Chordata,‭ ‬Reptilia,‭ ‬Sauropterygia,‭ ‬Pleisoauria.Species: C.‭
‬magnus,‭ ‬C.‭ ‬valdensis,‭ ‬C.‭ ‬snowii.Diet: Probably
piscivorous.Size: Uncertain sue to the assemblage of remains and
partial incomplete preservation of many specimens.Known locations:
Europe,‭ ‬North America and Australasia.‭ *‬Possibly not an accurate
representation of the genus.Time period: Cretaceous‭ (‬sometimes
credited as mid Jurassic to end of the Cretaceous‭)‬.‭ ‭*‬Possibly not an
accurate representation of the genus.[**Some specimens indicated as Post-Cretaceous when originally collected, Particularly the New Jersey specimens-DD]Fossil representation: Multiple
partial and incomplete remains.‭ ‬Possibly not all indicative of the genus.

The term most often attributed to Cimoliasaurus is‭
‘‬wastebasket taxon‭’ ‬due to the practice of some palaeontologists‭ ‬assigning
otherwise unidentifiable plesiosaur bones to the genus.‭ ‬This is why
geographical distribution for the genus covers Europe,‭ ‬North America,‭ ‬and
Australia and New Zealand,‭ ‬while the temporal range in the past has run from
the mid Jurassic to the very end of the Cretaceous period‭ (‬though sometimes
the range‭ ‬is cited as Early Cretaceous to‭ ‬the end of the
Maastrichtian‭)‬. Because of this the validity of Cimoliasaurus
as a genus remains dubious,‭ ‬but more may come from the remains attributed to
Cimoliasaurus such as the discovery of new plesiosaur genera.‭ ‬This has
happened already with the creation of the species Cimoliasaurus
laramiensis by Knight in‭ ‬1900,‭ ‬which was renamed as a species of Tricleidus‭
(‬T.‭ ‬laramiensis‭) ‬by Mehl in‭ ‬1912‭ ‬before eventually being raised
as a new genus called Tatenectes
by O'Keefe and Wahl in‭ ‬2003. With more in depth study it is probable
that one day Cimoliasaurus may one day be cleaned up enough to get an
accurate description of a specific genus.‭ ‬Such cases of‭ ‬a‭ ‬wastebasket
taxon being cleaned up is nothing new,‭ ‬with one of the best known examples
being that for the dinosaur Megalosaurus.

The Chilean and Antarctic Genus Aristonectes is one that was originally classified in Cimoliasaurus (in the late 1800s) and in fact includes specimens thought to have been more recent than the end of the Cretacreous-This too is disputed but I havee discussed the matter in connection with the "Patagonian Plesiosaurs" in a few cases it is thought that the area where the fossils were not even under the sea during the Cretaceous, they were thought to have been under the sea during the Paleocene and Eocene. It fed on small animals like shrimps.

Aristonectes

Aristonectes (meaning 'best swimmer') is an extinctgenus of plesiosaur from the Late Cretaceous of what is now South America and Antarctica. The type species is Aristonectes parvidens, first named by Cabrera in 1941. [Having been called called Cimiolasaurus before then]Aristonectes has been classified variously since the 1941 description, but a 2003 review of plesiosaurs conducted by Gasparini et al. found that Aristonectes was most closely related to elasmosaurid plesiosaurs like Elasmosaurus. A similar plesiosaur, Morturneria, may be a junior synonym of Aristonectes, the study found.Aristonectes has been recently placed within its own family, along with Tatenectes, Kaiwhekea, and Kimmerosaurus, by O'Keefe and Street (2009). Aristonectids are the sister family of the polycotylid cryptoclidoids.

Darren Naish mentioned the problem about classification in a recent blog and I nearly had a discussion about it then, but I found the situation to be too uncertain to make any definite statements. the original Cimiolasaurus of Leidy seems to be of the same family as Aristonectes. This family has similarirties both to the Cryptoclidids and to the Elasmosaurs but is also different than both of them. Cimiolasaurus has been reported from post-Cretaceous deposits: indeed, Leidy's initial finds were from a stratum identified as Pliocene, although this was later written off as impossible. The remains of the plesiosaur were however found mixed up with the remains of a Pliocene dolphin. The other fossils from other areas should be removed from the same genus, but there are also other fossils of PostCretaceous Plesiosaurs said to come from other areas and these might well belong to the original genus. The problem is still very far from being settled.

Skeleton of a related genus presumably in the same family, with reconstructed outline.

It should be noted that fossils of this family have been taken to indicate that the creatures were more tolerant of cold climate (including Antarctica!) and to be able to tolerate either freshwater or saltwater. They are modest-sized as Plesiosaurs go, mostly in the range of 15-30 feet long as adults. This also might be all we need for our purposes in dealing with Longnecked Cryptids reported in more modern times.

No comments:

Post a Comment

This blog does NOT allow anonymous comments. All comments are moderated to filter out abusive and vulgar language and any posts indulging in abusive and insulting language shall be deleted without any further discussion.

Popular Posts

In order to be fair and have more choices, there are now two Popular Posts lists: the first one is for the last 30 days and the second one is for all-time favorites. Some posts may appear on both lists temporarily.

Associated Sites

Disclaimer

In Accordance with Title 17 USC Section 107, any copyright material on display here is under Fair Use without any claim of ownership or any profit accrued by the display. The Material herein is for non-profit educational or criticism puposes only. Notwithstanding the provisions of Sections 106 and 106a, the fair use of a copyrighted work including reproduction and distribution of said material as specified in that section, for purposes of education, news reporting, commentary or criticism, scholarship or research, to persons who have expressed a prior interest in receiving such material for such purposes, is NOT an infringement.